Caption: Volcanic lightning. Time-exposure image of lightning in and around a large ash column produced during the 2010 Eyjafjallajokull volcanic eruptions. Volcanic lightning is the release of electric charge that builds up as rising ash mixes with the atmosphere. The activity under the Eyjafjallajokull glacier started in March, with a major eruption taking place on 14 April, sending ash high into the atmosphere. Carried by the wind, this ash led to the closure of large parts of European airspace for several days. This is a relatively long time-exposure image, taken on 18 April 2010.